Generally speaking, there are three phases of materials depending on temperature, known as solid phase, liquid phase and vapor phase. However, in 1888, an Austrian botanist named Friedrich Reinitzer discovered the fact that some materials have middle phase between solid phase and liquid phase.
This middle phase is called a liquid crystal (LC) because it has the optical anisotropy characterized by solid phase despite the appearance of liquid.
A shape of LC molecules is like a pole and each position is random, but the direction is regularly-arranged parallel to long axis of the molecules. They have a dielectric anisotropy and arrange the long axis parallel to the direction of electric field with applied voltage. Today, this characteristic has been utilized as ON/OFF light valve for displaying an image in LC projectors and displays.
2. Santec LC technology
Santec has developed and manufactured LC devices as one of core technologies for advanced optical devices and systems. Mass production line is 8 inch wafer process. Santec LC devices are characterized by wide viewing angle, high contrast ratio and high reliability resulting from adopting vertical aligned nematic (VAN) mode and inorganic LC alignment layer.
2.1 LCOS (Liquid Crystal On Silicon)
LCOS is micro-display and micro-projection technology for LC projector and rear-projection TV.
LOCS is normally reflective type LC panel consisting of reflective layer and LC on Si substrate. Switching elements and electric wires for driving LC are integrated on Si substrate under reflective layer with semiconductor manufacturing technology and the image is characterized by seamless and high pixel resolution.
Santec LCOS devices conform to WXGA (1280 x 768) and are suitable for various applications including head-mount display, holographic memory and high-end optical system.
2.2 LC devices for optical communication network
A change of LC dielectric constant anisotropy along with applied electric field enables to control optical phase and amplitude freely.Santec has developed various optical components and test instruments utilizing the LC controllability for advanced optical communication network. Santec LC devices are Telcordia qualified and high reliability is guaranteed in our components and instruments.
Wavelength blocker (WB) is multi-functional optical module for constructing ROADM (Reconfigurable Optical Add/Drop Multiplexer) nodes in next generation optical networks. The module outputs WDM (Wavelength Division Multiplexing) signals with arbitrary amplitude or blocking for any WDM channels. Santec WB adopts to reflective type LC devices with segment electrodes corresponding to WDM channel number for optical amplitude control.
Spectrum controllable tunable filter with LCOS technology that enables to create an arbitrary optical spectrum. The filter allows to design any complex optical filters for next generation optical communication networks, which were difficult to realize at conventional filter technologies.
The pixel pitch, width and number of LCOS chip are 5 µm, 4.7 µm and 2560, respectively. And 12 bit level of LC driving voltage makes possible high spectrum control resolution.
Santec will contribute to our society with unique optical products applying to our LC technology.